Rotary drum drier or the like



April 12, 193 8. B. SAGEBARTH ROTARY DRUM DRIER OR THE LIKE Filed Sept. 25, 1955 Patented Apr. 12, 1938 UNITED STATES PATENT OFFICE ROTARY DRUM DRIER OR THE LIKE man company Application September 25, 1935, Serial No. 42,113 In Germany October 2, 1934 4 Claims.

An application for patent has been filed in Germany No. S 115,596, V/82a, on the 2nd October 1934.

The present invention relates to a rotary drum 5 drier in which a drum is fitted internally with shelving for the purpose of showering the material which is being passed therethrough in order that a greater surface area of the material is presented for treatment by hot' or cool gases which are also passed through the drum.

It is well known that in order to obtain a better transfer of heat from-flowing fluids or materials to the walls of surrounding ducts that the walls are fitted with pin-like projections spaced short distances apart whereby, without increasing the speed at which the medium to be treated is to flow, a greater amount .of heat will be transferred from the material to the said walls. The additional amount of heat transferred from the ma- 0 terial to the said walls is not, however,due solely to the increased area of the surface presented by the walls and is not, therefore, in direct proportion thereto because when the current of air passing through the drum strikes against the pin-like projections it is whirled in eddies whereby an intensified contact is attained between the hot air or gases and the material being treated.

The above principle cannot, however, be advantageously applied to rotary drum driers which D are fitted with an internal construction which causes the material to be showered when the drum is rotated for the following reason. In the first place, it is necessary to restrict the height of the pin-like projections as otherwise they would 5 form cavities or pockets within which the material would be trapped and its progress through the drum thereby unduly delayed. On the other hand, however, it is essential that the pin-like projections should protrude above the surface 3 of the material in order that the air passing through the drum-is whirled i'nto eddies.

It is, therefore, the object of the invention to provide a construction which will enable th': current of air passing through the drum to be 5 whirled into eddies but which will not at the same time be subject to the above mentioned disadvantage and hinder unduly the progress of the material through the drum. This object is attained by the present invention in leaving the faces of the drying surface to which the projecting parts are fitted as plane as possible.

According to this invention a rotary drum for drying, calcining or cooli; purposes comprises a shell and a plurality of heat transfer members located within said shell which are shaped to provide-shelving over which the material to be treated is made to pass in thin layers, the said shelving having disposed thereon in spaced relationship a numberof projecting fins which are positioned substantially transversely to the direction of travel of the material through the drum and which fins serve to whirl the dry gases into eddies.

It has been found that an internal shelvingof H-shaped section is particularly suitable for this purpose, it being understoodthat, in order to ensure a better heat transfer and a satisfactory eddying of the air the projecting parts or fins should be arranged, preferably, but not necessarily on the outer lateral straight faces of the flanges of the H-shaped members. It is also possible to arrange the two halves of the flanges which meet at the central web at a slight angle so that the troughs formed between the two flanges are enlarged or flared at their outer ends. It is important that a suitable and favourable type of shelving should be used which, owing to the arrangement of these members relatively to one another will ensure a satisfactory showering of the material under treatment, said material travelling over the approved path and showering down as many as four times during each revolution of the drum.

In this connection, it is further possible to ensure, by a suitable arrangement of the heat transfer members or fins, an automatic and continuous banking up of the material under treatment, which otherwise might travel too rapidly over the plane faces of the internal shelves, thus ensuring a greater uniformity of drying in the finished product and also an increased capacity.

The accompanying drawing shows, diagrammatically and by way of example, one constructional form of the present invention.

Fig. 1 is a cross section through a rotary drum drier provided with internal showering shelving; and

Fig. 2 is a longitudinal section through the said drum drier.

Referring to the drawing:-- 1

Within a rotary drying drum or shell s, H-

' shaped distributing members a, which form two troughs with their bases disposed end to end, are

arranged in such a way in relation to each other that two opposite troughs of adjacent members are staggered in regard to each other.

The opposing surfaces of the flanges b of two adjacent distributing members are fitted over their whole width with the heat transfer or eddying members respectively, whereas the troughlike spaces It formed by the central web 10 between the flanges b oi each distributing member would remain, preferably, free of said eddylng members or projecting parts. The path of the material, which during one revolution showers down as many as four times, is shown by the broken lines at c and d. Outside the regular system viz., in the vicinity of the drum shell, only in some parts showering systems of this kind may be obtained, where the material showers down two or three times only passes through the drum to bank up therein in a longitudinal sense only. While the flns g are shown only on certain of the flanges of the H members in Figure 1 of the drawing, there may be as many of such fins as are desired.

The flanges or adjacent distributing members may overlap each other as shown at d or they may just reach each other as shown at c.

In order to flx or support the distributing members inthe drum section (in Figure 1, part of the members is shown without any flxing) either step-shaped supports e may be arranged at suitable intervals or the central webs of the distributing elements may be interconnected, or by other suitable means. These fixing means should be arranged in such a way that they do not interfere or, at least, not interfere to any extent with the travel of the material through the free section of the drum.

I claim:

1. A rotatable heat exchange drum comprisin a shell, a plurality of shelves arranged in staggered rows in said shell and substantially longitudinal thereof and projecting flns provided on said shelves and extending lengthwise in a direction substantially transverse to the axis of the shell.

2. A rotary drum, comprising a shell, a plurality of members of H cross-section arranged in staggered relationship within said shell, and angularly projecting members arranged on the flanges of the H-section members and extending lengthwise at substantially right angles to the iongitudinal axis of the drum.

3. A rotary drum as claimed in claim 2, in which the heat transfer members are arranged at longitudinal distances along the flanges of the H-section members in order to provide continuous banking up of the material under treatment.

A- rotary drum comprising a shell, a plurality of members of H cross-section arranged in staggered relationship within and substantially parallel to the axis of said shell, projecting heat transfer fins arranged on the flanges of the H- section members and extending transversely of the longitudinal axis of the H members, and

means supporting said H-section members including a step shaped support extending across the shell.

BERNHARD SAGEBARTH. 

